Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau |
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| Authors: | J Cao Y Gong E T Yeh N M Holden J F Adamowski R C Deo M Liu J Zhou J Zhang W Zhang S Zhang D Sheng S Yang X Xu M Li Q Feng |
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| Institution: | 1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou, China;2. Department of Geography, University of Colorado Boulder, Boulder, CO, USA;3. UCD School of Biosystems and Food Engineering, University College Dublin, Agriculture and Food Science Centre, Belfield, Dublin 4, Ireland;4. Department of Bioresource Engineering, Faculty of Agricultural and Environmental Science, McGill University, Québec, QC, Canada;5. School of Agricultural, Computational and Environmental Sciences, International Centre for Applied Climate Sciences, Institute of Agriculture and Environment, University of Southern Queensland, Springfield, Qld, Australia;6. Key Laboratory of Ecohydrology of Inland River Basin, Alashan Desert Eco‐Hydrology Experimental Research Station, Cold and Arid Regions Environmental Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China;7. College of Chemical Engineering, Northwest Normal University, Lanzhou, China;8. College of life sciences, Northwest Normal University, Lanzhou, China |
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| Abstract: | Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 107 and 6.15 × 107 Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist. |
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| Keywords: | land use policy grazing management carbon storage trampling global carbon cycle policy scenarios |
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